US3001056A - Ceiling heater and ventilator - Google Patents

Description

Sept. 19, 1961 w. A. SPEAR CEILING HEATER AND VENTILATOR 2 Sheets-Sheet 1 Filed Oct. 1, 195a United States Patent 3,001,056 CEILING HEATER AND VENTILATOR Walter A. Spear, Cincinnati, Ohio, assignor to Nutone, Inc., Cincinnati, Ohio, a corporation of New York FiledOct. 1, 1958, Ser. No. 764,680 Claims. (Cl. 219--39) This invention relates to a combined room heater and ventilator, adapted, on the one hand, to drive air over a heating element into a room, and on the other hand to exhaust stale air fromthe room.

In devices of this type, it is important from the standpoint of the utility of the heating element to pass a convection current of air over the heating element during its operation. If it were not for the convection air being driven past the heating element, the principal heat transfer agent would be radiation, and such convection currents as might exist would merely carry the heat .in an upward direction. Not only is it important from the standpoint of sound heat engineering design to provide,

the convection fan, but, additionally, Underwriters Laboratories requires the utilization of a convection fan in combination with a heating element for approval of Underwriters Laboratories to be obtained.

An appliance conforming to these requirements is the subject of U.S. Patent 2,689,906, owned by the assignee of the present invention. patent is a combination including av heating element, a single fan driven by a reversible motor, and an exhaust port. The combination is provided with means for driving the motor in one direction to operate the fan as a convection type fan that is, one. which will circulate air over the heating element when the heating element is energized, and to drive the motor in the opposite direction when the heating element is de-energized. so that the.

fans, each specifically designed for optimum performance of its particular function, it is possible to avoid the disadvantage of requiring a compromise design of a single fan which performs neither .of the functions of exhaust and circulation at optimum efficiency. f

It has been still another objective of the invention to provide a unidirectional motor driving a convection'fan for passing air over a heating element and simultaneously driving an exhaust fan with means for rendering the exhaust fan inoperative when the heating element is energized.

. It has been yet another objective of the inventionto provide, in a device of the type described above, a pivotally mounted exhaust port gate operably connected to a bimetallic element the bimetallic element being disposed adjacent the heating element so as to pivot the gate'to a position closing theexhaust'port when the heating element is energized, thereby rendering the exhaust fan inoperative. I j Y i e Another objective of the invention has been to provide; in a device of the type described above, electric circuits controlling the operation of the motor and the heating element, the circuits being interlocked so that it is impossible to energize the heating element until themotor driving the convection fan is energized. These and other objectives of the invention becomemore ead y pp re t t Qm1 e o1 0 s cta cdd The device disclosed inthe scription taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a bottom plan view of the invention;

FIGURE 2 is a cross-sectional view taken along lines 22 of FIGURE 1;

s FIGURE 3 is a cross-sectional view taken along lines 3-3 of FIGURE 1; and a FIGURE 4 is a circuit diagram of the invention.

The appliance is designed principally for installation in the ceiling of a bathroom but, of course, it can be useful in other types of rooms and in other locations in a room. The principal supporting element of the. appliance is a housing 10 having an annular flange 11 which is mounted flush with a ceiling or the like by means of lugs 12 angularly spaced about the periphery of the flange 11 and fixed thereto as by Welding, riveting, or the like. At the upper portion of the housing 10 an aperture 13 is provided through which a conduit 14 passes to form an exhaust port. The conduit 14 is terminated by a bell 15 to receive additional conduit by which the exhaust gases are passed to the exterior of the building.

A unit 16 containing the principal elements of the invention is removably mounted to the housing 10 by means of a hinge 17 and lugs 18 bolted to a bracket 19 fixed to the housing. The hinge 17 and bracket 19 support a sleeve 20. Concentric with the sleeve 20 is a tubular receptacle 21 within which an electric lamp 22 mounted on a strap 27 is housed. The receptacle 21 is spaced from the sleeve 20 and supported therefrom by vanes 23 which are channel-shaped in cross-section as illustrated in FIG- URE 1. The lower edge of each vane 23 is recessed as at 24 to receive a circular electric resistance heating element 25. The heating element is supported by radial brackets 26. A motor 30 is supported above the sleeve 20 by supports 31 bolted at 32 to the sleeve 20. The members 31 carry an apertured plate 33 on which the motor 30 rests. A shaft 34 extends through the motor and supports at the lower end 35 thereof a circulating or convection fan 36 secured to the shaft 34 by a set screw 37. The operating surface of the fan 36 is concentrated at the extremity 38 thereof to cooperate with the vanes 23 and the annular passageway formed between the sleeve 20 and receptacle 21.

At the upper end 40 of the shaft 34 is mounted a squirrel cage type fan having vanes 42 which rotates within a volute type housing 43. The lower portion of the housing 43 has an aperture provided by a cowling 44 which forms an inlet passageway for the squirrel cage exhaust fan 41. Thehousing 43 also has a tangential outlet 45 which, when the unit 16 is supported in its proper position is connected to the conduit 14, which thereby forms a continuous extension of the outlet 45.

Disposed in the exhaust port formed by the outlet 45 and the conduit .14 is a butterfly gate 50 fixed to a pivot pin 51, the pivot pin being journaled at its ends in the housing 43. The gate 50 has an open position indicated element is partially supported by a bracket 58 in which the pin 56 is journaled and is partly supported by the heating element 25 upon which the element 54 rests. The outer end 60 of the bimetallic element is secured to the tubular support member 20 by a metal screw 61 which also secures one end of the bracket 58 to the tubular support. The other end of the bracket is secured by a similar metal screw 62 to the support 20.

Electrical connections to the lamp, the motor and the heating element are made by suitable conductors" (de scribed in connection with FIGURE 4) which are passed into' an outlet box 63 where a thermal protector and suitable'terminal connectors are provided for making connections to the required wall switches.

The combination of the high volume squirrel cage exhaust fan -41 and the low volume convection fan 36, with the exhaust fan being placed above the convection fan as illustrated in FIGURE 2 of the drawings," such that air moved by either fan passes through the common. annular passageway which exists between the circular.

lamp receptacle-21 and the sleeve 20, overcomes an objection to the combination disclosed in the assignees U.S.

The lower portion of the assembly is attractively enguard 67 is removably mounted below the heating element 25 by resilient stringers 71 which pass through holes 72 in the sleeve 20. I

The circuit diagram of FIGURE'4 illustrates the manner in which the electrical units of the combination are energized and the manner in which the circuits are inter.- locked to permit energization of the heating element 25 only when the motor 30 is energized. The circuit is connected to a 110 volt power supply indicated at 75. The lamp 22 is connected to the power source through a switch 76 and the motor is connectedto the power source by a switch 77. A conductor 78 connects the. switch to the fan motor 30 at 79 and connects the switch 77 to a heater switch 80. Thus, a parallel circuitof heater. and motor is provided, the parallel circuit being connected in. series with the switch 77, whereby the switch 77 controls the operation t both legs of the parallel circuit. In parallel with the heater element is a pilot light 81 to be associated with the wall switches and which will be energized with the heater upon the closing of the switch 80 (assuming that the motor switch 77 has previously been closed) to serve as an indicator that the heating'element is energized, a situation which might nototherwise be easily determined.

FIGURE 4 also contains a diagrammatic illustration of the positioning of the bimetal 54 adjacent the heating element 25 and the connection 57 to the gate 50.

The' operation of the invention can best be understood by reference to FIGURE 4. When it is desired to operate the exhaust fan, the switch -77 is closed and the exhaust fan motor 30 is directly energized by the power source 75. Under these conditions, including the fact that the heating element is cold, the gate 50 will remain in the openposition indicated at 52 in FIGURE 1, permitting the exhaust fan to remove air from the room;

The exhaust fan and its cooperating housing 43 are designed for considerably greater efficiency than-the C011. vection fan 36. As a consequence, the exhaust fan, which is operating in opposition to the convection fan, drives many times the volume of air than does the convection fan so that'the flow of air is up and out through the exhaust port.

If heating rather than ventilating should be desired, the switch 80 is closed along with the switch 77. Initially, because of the greater efficiency of the exhaust fan, the operation will be one of exhausting the air bnt within a short time the heating element 25 will be heated enough I to expand the bimetal 54. The expansion of the bimetal 54 which is fixed at its outer end will cause the rotation of the inner end thereof through approximately 45 degrees to swing the gate 50 to the closed position illustrated at 53 in FIGURE 1. Closing the exhaust port will effectively render the exhaust fan inoperative so that the convection fan 36 will be fully effective. The convection fan 36 will draw air through the grill work 6466 and force it downwardly through the annular passageway between the members 20 and 21.. The downwardly moving air will pass over the heating element 25, picking'up heat therefrom and conveyi'ng it into the-room below.

Patent No. 2,689,906. In the patented'combination, in' order to meet underwriters requirements, it is necessary that the convection fan be energized at the same time the heating element is energized. Thus, in the short time while the heating element is heating up, the convection fan drives a column of chilling air down into the room below. By contrast, when the heater in the com-.

bination disclosed herein started, the butterfly gate 50 is open and when the squirrel cage blower starts, it robs the convection fan 36 of its air so that even though the convection fan is rotating with the blower, the air moves up through the passageway between the lamp housing 21 and sleeve 20 and out through the butterfly gate 50 into the exhaust duct' Now, as the heater coil starts heating up, the butterfly gate begins closing, so that the squirrel cage exhaust fan 41 becomes decreasingly effective and when the heating element reaches its peak temperature, the squirrel fcage exhaust fan is completelyv ineflective, serving merely as a flywheeLLand the convection fan takes over to drive a column of air over the heating element 25 down into the room. In substance, therefore, the squirrel cage exhaust fan starves the convection fanwhen the heater is just turned on and during the period that the element heats up, the squirrel cage exhaust fan becomes less and less etfective while the convection fan becomes more and more efiective. This eliminates the chilling column of air of the patented combination. 1

i It should be understood that whereas the illustrated form of the invention is preferred because of the simplicity and efliciency of the operating elements, there are many variations which can be made in the invention without departing from the spirit and scope thereof. For example, the gate 50 could be operated by a solenoid connected in series with the pilot light 81, the solenoid driving a rack engaged by a pinion mounted-on the pin 51. Thus, direct operation of the gate would be afforded without relying on the heating of the bimetal 54 for the operation of the gate. Alternatively, the heat of the element 25 might be utilized through the agency of a thermocouple, the electrical energy of the thermocouple i 'the above description, what is deemed to be the most to each other, said exhaust fan being of greater air propractical and eflicient embodiment of the invention, it should be well understood that the invention is not limited to such embodiment as changes may be made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

I claim:

1. A11 appliance comprising a motor, an exhaust fan and a circulating fan driven by said motor in opposition to each other, said exhaust fan being of greater air propelling'efficiency than said circulating fan and tending to starve said circulating fan, a heating element in the path of flow from said circulating fan, and means automatically rendering said exhaust fan inefiective to starve said circulating fan when said heating element is energized.

2. An appliance comprising a motor, an exhaust fan and a circulating fan driven by said motor in opposition pelling efliciency 'thansaid circulating fan and tending to starve said circulating fan, a heating element in the path of flow from said circulating fan, and bimetal means mounted adjacent said heating element for automatically rendering said exhaust fan ineffective to starve said circulating fan when said heating element is energized.

3. An appliance comprising a frame, a motor mounted by saidframe, an exhaust fan and a circulating fan driven by said motor in opposition to each other, said exhaust fan being of greater air propelling efficiency than said circulating fan and tending to starve said circulating fan, an exhaust port formed in said frame, said exhaust fan tending to drive air through said exhaust port, a gate movable to open and closed positions such that when said gate is in open position said exhaust fan starves said circulating fan and propels air through said port and such that when said gate is closed said exhaust fan is rendered inefiective to starve said circulating fan, a heating element in the path of air flow from said circulating fan, and means automatically closing said gate when said heating element is energized.

4. An appliance comprising a motor, an exhaust fan and a circulating fan driven by said motor in opposition 20 to each other, said exhaust fan being of greater air propelling efficiency than said circulating fan and tending to starve said circulating fan, a heating element in the path of flow from said circulating fan, circuit means including a switch for connecting said motor to a voltage 26 source, circuit means including a switch for connecting said heating element to a voltage source, means interlocking said respective circuit means so that said heating element can be energized only when said motor is energized, and means automatically rendering said exhaust fan ineffective to starve said circulating fan when said heating element is energized.

5. An appliance comprising a frame, an exhaust port in said frame, an exhaust fan mounted to propel air through said port, a gate pivotally mounted in said port and movable between open and closed positions therein, a motor having a shaft passing therethrough, means connecting said exhaust fan to one end of said shaft, a circulating fan connected to the other end of said shaft, said exhaust fan being of greater air propelling efficiency than said circulating fan and starving said circulating fan when said gate is in open position, a heating element disposed in the flow path of said circulating fan, a spirally wound bimetal strip mounted adjacent and in heat conducting relationship to said heating element, and means connecting said bimetal element to said gate whereby said gate is moved to closed position when said heating element is energized.

References Cited in the file of this patent UNITED STATES PATENTS 1,041,322 Mics Oct, 15, 1912 1,749,039 Lincecum Mar. 4, 1930 2,351,096 Blue June 13, 1944 2,689,906 Corbett Sept. 21, 1954 2,870,319 Ford Jan. 20, 1959 2,875,316 Ford et al. new. Feb. 24, 1959

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